Method and device for treating vision impairment

ABSTRACT

Disclosed is a wearable optical devices for a human subject, comprising: a transparent lens; a wearable frame configured to maintain the lens in front of an eye of a human subject; a transparent pixelated active optical element where the pixels of the active optical element have an optical property with a changeable value; an eye tracker; and a controller configured to set a value for an optical property of the pixels of the active optical element so as to create an image mask through which at least some of the light reaching the feye passes through, thereby modifying the image formed on the retina of the first eye.

RELATED APPLICATION

The present application is a Continuation Application of U.S. Ser. No.17/503,321, a 371 of PCT/IB2021/052813 having an International FilingDate of Apr. 5, 2021 and which gains priority from UK patent applicationGB 2005040.7 filed Apr. 6, 2020, all which are included by reference asif fully set-forth herein.

FIELD AND BACKGROUND OF THE INVENTION

The invention, in some embodiments, relates to the field ofophthalmology and, more particularly but not exclusively, to opticaldevices useful for non-invasive treatment of vision impairments.

In the art, it is known to modify an image formed on the retina of aneye to treat a vision impairment.

U.S. Pat. No. 7,832,859 (Auckland Uniservices Ltd.) and US 2012-0113386and U.S. Pat. No. 8,899,746 (both to Coopervision International HoldingCompany) all teach contact lenses that modify the image formed on theretina of an eye for preventing and/or reducing the progression ofmyopia and/or hyperopia.

WO 2018/055618 to the Applicant and U.S. Pat. No. 10,251,546 toNottingham University teach treatment for amblyopia of a subject havingan amblyopic eye and a non-amblyopic eye by modifying an image displayedto the non-amblyopic eye, specifically, degrading at least part of theimage so that the amblyopic eye is forced to be used.

US 2019/0200858 to the Applicant teaches display of a modified image toa person suffering from vision impairment due to macular damage to treatthe eye.

The methods and devices disclosed in these and other art have one ormore disadvantages for treating vision impairments. It would be usefulto have methods and devices that have at least one advantage over theart.

SUMMARY OF THE INVENTION

Some embodiments of the invention herein relate to devices useful in thefield of ophthalmology and, in some particular embodiments, useful forthe non-invasive treatment of various vision impairments. Someembodiments of the teachings herein are useful for one or more of:preventing the development, stopping the progression, reducing theseverity of existing visual deficits and improving the quality of lifein cases such as refractive errors including myopia, hyperopia andanisometropia; vision degeneration caused by macular degeneration; andamblyopia.

According to an aspect of some embodiments of the teachings herein,there is provided a wearable optical device for a human subject,comprising:

a. a transparent lens having a distal surface and a proximal surface;

b. a wearable frame configured, when worn by a human subject, tomaintain the proximal surface of the lens in front of a first eye of thesubject at a distance of not less than 5 mm and not more than 50 mm fromthe surface of the cornea of the first eye so that at least part of thevisual field of the first eye is covered by the lens when the gazedirection of the first eye is straight ahead;

c. a transparent pixelated active optical element comprising at least100 independently-addressable pixels, each one of the pixels having anoptical property with a changeable value, the active optical elementphysically associated with the frame and/or the lens so that at leastpart of the visual field of the first eye is covered by both the lensand the active optical element;

d. an eye tracker configured to determine and report the gaze directionof the first eye; and

e. a controller having a digital memory configured to:

-   -   i. receive from the eye-tracker a determined gaze direction of        the first eye; and    -   ii. at a repetition rate, set a value for the optical property        of the at least 100 pixels of the active optical element so as        to create an image mask (using the active optical element)        through which at least some of the light reaching the first eye        passes through, thereby modifying the image formed on the retina        of the first eye,

-   wherein the value for the optical property is based on a received    gaze direction and the optical power of the lens, and

-   wherein the controller, the lens and the active optical element are    together configured so that during operation of the optical device,    at least a portion of the visual field of the first eye is degraded    by the optical power of the lens and/or by the image mask.

In some such embodiments, the optical device further comprises: a pupilsize determiner configured to determine and report the size of the pupilof the first eye, and the controller is configured to receive from thepupil size determiner a determined pupil size of the first eye, and thevalue for the optical property of the pixels is also based on a receivedpupil size.

According to an aspect of some embodiments of the teachings herein,there is also provided a wearable optical device for a human subject,comprising:

a. a transparent lens having a distal surface and a proximal surface;

b. a wearable frame configured, when worn by a human subject, tomaintain the proximal surface of the lens in front of a first eye of thesubject at a distance of not less than 5 mm and not more than 50 mm fromthe surface of the cornea of the first eye so that at least part of thevisual field of the first eye is covered by the lens when the gazedirection of the first eye is straight ahead;

c. a transparent pixelated active optical element comprising at least100 independently-addressable pixels, each one of the pixels having anoptical property with a changeable value, the active optical elementphysically associated with the frame and/or the lens so that at leastpart of the visual field of the first eye is covered by both the lensand the active optical element;

d. an eye tracker configured to determine and report the gaze directionof the first eye; and

e. a controller having a digital memory configured to:

-   -   i. receive from the eye-tracker a determined gaze direction of        the first eye; and    -   ii. at a repetition rate, set a value for a the optical property        of the at least 100 pixels of the active optical element so as        to create an image mask (using the active optical element)        through which at least some of the light reaching the first eye        passes through, thereby modifying the image formed on the retina        of the first eye,

-   wherein the value for the optical property is based on a received    gaze direction and the optical power of the lens, and

-   wherein the optical device further comprises:    -   a pupil size determiner configured to determine and report the        size of the pupil of the first eye, and the controller is        configured to receive from the pupil size determiner a        determined pupil size of the first eye, and the value for the        optical property of the pixels is also based on a received pupil        size.

In some such embodiments, the controller, the lens and the activeoptical element are configured so that during operation of the opticaldevice, at least a portion of the visual field of the first eye isdegraded by the optical power of the lens and/or by the image mask.

BRIEF DESCRIPTION OF THE FIGURES

Some embodiments of the invention are described herein with reference tothe accompanying figures. The description, together with the figures,makes apparent to a person having ordinary skill in the art how someembodiments of the invention may be practiced. The figures are for thepurpose of illustrative discussion and no attempt is made to showstructural details of an embodiment in more detail than is necessary fora fundamental understanding of the invention. For the sake of clarity,some objects depicted in the figures are not to scale.

-   In the Figures:

FIGS. 1A-1C are schematic depictions of an exemplary embodiment of anoptical device according to the teachings herein in perspective viewfrom the front (FIG. 1A), in view from the back (FIG. 1B) and in topview (FIG. 1C) having a single active optical element with a visualfield that is equal to that of the associated lens;

FIGS. 2A-2D depict different embodiments of how an active opticalelement is associated with a lens of an optical device according to theteachings herein;

FIG. 3 is a schematic depiction of an exemplary embodiment of an opticaldevice according to the teachings herein from the back having an activeoptical element with a visual field that is smaller than that of theassociated lens;

FIGS. 4A-4C are schematic depictions of an exemplary embodiment of anoptical device according to the teachings herein in perspective viewfrom the front (FIG. 4A), in view from the back (FIG. 4B) and in topview (FIG. 4C) having two active optical elements, one for each eye of asubject, each having a visual field that is equal to that of theassociated lens;

FIGS. 5A and 5B depict an embodiment where an optical device such asdepicted in FIGS. 4A-4C is used to create an image mask for treatingrefractive errors such as myopia; and

FIGS. 6A and 6B depict an embodiment where an optical device such asdepicted in FIGS. 1A-1C is used to create an image mask for treatment ofamblyopia or AMD.

DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

Some embodiments of the invention herein relate to devices useful thefield of ophthalmology and, in some particular embodiments, useful forthe non-invasive treatment of various vision impairments.

Herein is disclosed a wearable optical device, which in some preferredembodiments resembles eyeglasses. The wearable optical device includesat least one transparent pixelated active optical element associatedwith a lens, the active optical element configured to create an imagemask through which light passes before reaching the eye of the personwearing the optical device. The light passes through both the lens andthe image mask, so that the image formed on the retina of the eye ismodified by the image mask. In embodiments where the lens is arefracting lens having a non-zero optical power, the image formed on theretina of the eye is modified by the image mask and the refracting lens.

The image mask is created in such a way so that the image formed on theretina has some utility in the treatment of a vision impairment. Forexample, in some embodiments the image formed helps the subject wearingthe optical device see better, that is to say, an effect of a visionimpairment is ameliorated. In some preferred embodiments, the imageformed is a therapeutic image which is configured to affect a persistentchange in how the brain perceives input from the eye and/or to stimulatean actual physical change in the eye itself. It has been found that insome preferred embodiments, for the formed image to have the desiredutility, at least a portion of the visual field of the eye is degradedby the optical power of the lens and/or by the image mask.

In some embodiments, the lens is a plano lens, the active opticalelement is a tunable lens (where a changeable optical property of thepixels allows the active optical element to change the optical power ofthe active optical element) and a desired image mask is created so thatthe active optical element acts as a lens to form the desired image onthe retina.

In some embodiments, the lens is a refractive lens, the active opticalelement is a tunable lens and a desired image mask is created based onthe optical power of the lens so that the active optical element acts asan additional lens together with the lens to form the desired image onthe retina. The image mask is also created based on the gaze directionas determined by an eye tracker. Some such embodiments can be consideredas maintaining the image mask at the same position relative to the gazedirection of the eye. In such a way, the image mask is created to ensurethat an image-modification is continuously located on the correctlocation of the retina.

As known in the art, the size of the pupil effects how incoming light isrefracted onto the retina. For example, it is known that under equalparameters, a larger pupil size leads to a less sharp image formed onthe retina compared to a smaller pupil size. To account for this, insome embodiments, the image mask is created also based on pupil size asdetermined by a pupil size determiner to ensure that a desired image isformed on the retina. In some such embodiments, the exact image maskthat is created accounts for ray tracing that is dependent on thedetermined pupil size.

It is herein disclosed that a wearable optical device according to theteachings herein can be used for non-invasive treatment of variousvision impairments, in some embodiments useful for one or more of:preventing the development, stopping the progression, reducing theseverity of extant vision impairments and improving the quality of lifesuch as refractive errors including myopia, hyperopia and anisometropia;vision degeneration caused by macular degeneration; and amblyopia.

An exemplary embodiment of a wearable optical device according to theteachings herein, optical device 10 is schematically depicted in FIG. 1A(perspective view from the distal side), FIG. 1B (view from the backtoward the proximal side) and FIG. 1C (view from the top). According toan aspect of some embodiments of the teachings herein, there is provideda wearable optical device 10 for a human subject, comprising:

a. a transparent lens 12 having a distal surface 14 and a proximalsurface 16;

b. a wearable frame 18 configured, when worn by a human subject 20, tomaintain proximal surface 16 of lens 12 in front of a first eye 22 a ofsubject 20 at a distance 23 of not less than 5 mm and not more than 50mm from the surface of the cornea of first eye 22 a so that at leastpart of the visual field of first eye 22 a is covered by lens 12 whenthe gaze direction of first eye 22 a is straight ahead;

c. a transparent pixelated active optical element 24 comprising at least100 independently-addressable pixels, each one of the pixels having anoptical property with a changeable value, active optical element 24physically associated with frame 18 and/or lens 12 so that at least partof the visual field of the first eye 22 a is covered by both lens 12 andactive optical element 24,

d. an eye tracker 26 configured to determine and report the gazedirection of first eye 22 a; and

e. a controller 28 having a digital memory configured to:

-   -   i. receive from eye-tracker 26 a determined gaze direction of        first eye 22 a; and    -   ii. at a repetition rate, set a value for the optical property        of the at least 100 pixels of the active optical element 24 so        as to create an image mask through which at least some of the        light reaching first eye 22 a passes through, thereby modifying        the image formed on the retina of first eye 22 a,

-   wherein the value for the optical property is based on a received    gaze direction and the optical power of lens 12.

In device 10, controller 28, lens 12 and active optical element 24 aretogether configured so that during operation of device 10, at least aportion of the visual field of first eye 22 a is degraded by the opticalpower of lens 12 and/or by the image mask.

In optical device 10, eye tracker 26 is also configured to function aspupil size determiner to determine and report the size of the pupil offirst eye 22 a, and controller 28 is also configured to receive such adetermined pupil size and to set a value for the optical property of thepixels also based on the received pupil size.

In device 10 depicted in FIGS. 1A-1C, active optical element 24 ispositioned before lens 12 in intimate contact with distal surface 14,where the visual field of active optical element 24 is equal to that oflens 12. As a result, it is difficult to discern the exact location ofactive optical element 24 and lens 12 in FIGS. 1B and 1C. In FIG. 1A,the edge of active optical element 24 meeting frame 18 is marked in greycolor.

Power Supply

Some components of the optical device require electrical power foroperation, for example, the active optical element, the controller, theeye tracker and, where present, the pupil size determiner. Any suitablepower supply can be used to provide the required electrical power.

In some embodiments, the optical device comprises a holder in which apower supply such as batteries (preferably but not necessarilyrechargeable) can be reversibly placed.

Alternatively or additionally, in some embodiments, the optical devicecomprises an integral electrical power supply for providing electricalpower for operation of components, e.g., integral rechargeablebatteries.

Alternatively or additionally, in some embodiments, the optical devicecomprises an input for accepting electrical power for operation ofcomponents from an external electrical power supply. For example, insome embodiments, the optical device comprises an input such as a port,e.g., a USB port which can accept power from an external power source.

Optical device 10 depicted in FIGS. 1A-1C includes an integralrechargeable battery 30 as an electrical power source which can berecharged via a USB port 32. USB port 32 is also functional for datatransfer to and from controller 28.

Frame

As noted above, an optical device according to the teachings hereincomprises a wearable frame configured, when worn by a human subject, tomaintain the proximal surface of the lens in front of a first eye of asubject at a distance of not less than 5 mm and not more than 50 mm fromthe surface of the cornea of the first eye so that at least part of thevisual field of the first eye is covered by the lens when the gazedirection of first eye is straight ahead.

As used herein, the phrase “at least part of the visual field of thefirst eye is covered by the lens” and similar such phrases mean that atleast some light entering the eye through the visual field thereofpasses through the lens.

The wearable frame is any suitable wearable frame that supports the lensin the position as described above. Typically, the lens is physicallyassociated with the frame. In some preferred embodiments, the wearableframe is an eyeglasses frame, having a bridge configured to rest on thenose of the subject and arms to rest behind the ears of the subject.optical device 10 depicted in FIGS. 1A-1C comprises a wearable frame 18that is an eyeglasses frame that includes a bridge and two arms. Other,non-depicted, embodiments of an optical device according to theteachings herein have other frames.

Transparent Lens

An optical device according to the teachings herein comprises atransparent lens having a distal surface and a proximal surface. By“transparent” is meant that the lens allows enough light reflected froman object to pass through the lens so that the object can be distinctlyseen.

Plano Lens

In some embodiments, the lens is a plano lens as known in the art, hasno optical power.

Refracting Lens

In some embodiments, the lens is a refracting lens having a non-zerooptical power, thereby configured to refract light passing therethrough.

In some such embodiments, the refracting lens is configured to at leastpartially correct refractive errors in at least part of the visual fieldof the first eye of the subject for which the optical device isintended. Additionally or alternatively, in some such embodiments, therefracting lens is configured to degrade at least a portion of thevisual field of the subject for which the optical device is intended.

In some such embodiments, the lens is a simple mono-focal refractinglens having a single constant optical power over the entire lens.Alternatively, in some such embodiments the lens is a complex refractinglens, having at least two portions, each having a different opticalpower (e.g., bifocal, multifocal or progressive lens), for example, aportion for near-vision and a different portion for far-vision. In someembodiments, the lens has at least two different portions configured toprovide a therapeutic effect. For example, in some embodimentsconfigured for treatment of myopia a first central portion of the lensis configured to focus light on the retina of the subject and a secondperipheral portion of the lens is configured so as not to focus light onthe retina of the subject. The utility of such an embodiment isdiscussed hereinbelow in greater detail.

The lens is any suitable size. In some embodiments, the frame and lensare together configured so that at least 30% of the visual field of thefirst eye is covered by the lens when the gaze direction of the firsteye is straight ahead. In some embodiments, at least 40%, at least 50%,at least 60% and even at least 70% of the visual field of the first eyeis covered by the lens when the gaze direction to the first eye isstraight ahead. In preferred embodiments, the lens covers at least 70%of the visual field in the primary gaze.

Active Optical Element

An optical device according to the teachings herein comprises atransparent pixelated active optical element comprising at least 100independently-addressable pixels, each one of the pixels having anoptical property with a changeable value, the active optical elementphysically associated with the frame and/or the lens so that at leastpart of the visual field of the first eye is covered by both the lensand the active optical element. By “transparent” is meant that theactive optical element has at least one state that allows enough lightreflected from an object to pass through the optical element so that theobject can be distinctly seen. As used herein, the phrase “at least partof the visual field of the first eye is covered by both the lens and theactive optical element” and similar such phrases mean that at least somelight entering the eye passes through both the lens and the activeoptical element.

In some embodiments, the active optical element is secured to a surfaceof the lens. In some such embodiments, the active optical element issecured to the distal surface of the lens. In some embodiments, theactive optical element is secured to the proximal surface of the lens.In some embodiments, the lens and the active element are combined to beone element without any physical separation between the two.

In FIG. 2A, a lens 12 is depicted in cross section with an activeoptical element 24 secured to a proximal surface 16 of lens 12. In FIG.2A, the part of the visual field of an eye that is covered by both lens12 and active optical element 24 is smaller than the part of the visualfield of the eye that is covered by lens 12.

In FIG. 2B, a lens 12 is depicted in cross section with an activeoptical element 24 secured to a distal surface 14 of lens 12. In FIG.2B, the part of the visual field of an eye that is covered by both lens12 and active optical element 24 is the same as the part of the visualfield of the eye that is covered by lens 12.

In FIG. 2C, a lens 12 is depicted in cross section with a firstsubcomponent 24 a of the active optical element secured to a proximalsurface 16 of lens 12 having pixels where the optical property with achangeable value is light transmission and a second subcomponent 24 b ofthe active optical element 24 secured to a distal surface 14 of lens 12having pixels where the optical property with a changeable value is aproperty of the pixels that provides controllable optical power of theactive optical element. In FIG. 2C, the part of the visual field of aneye that is covered by both lens 12 and active optical element 24 is thesame as the part of the visual field of the eye that is covered by lens12.

In FIG. 2D, is depicted in cross section a lens 12 which is one of thecomponents of an active optical element 24, specifically, the backingcomponent that supports other parts of active optical element 24.

Shape of the Active Optical Element

The active optical element has any suitable shape.

In some embodiments, the active optical element is circular. In opticaldevice 10 depicted in FIGS. 1A-1C, active optical element 24 isrectangular.

In an optical device 34 depicted in FIG. 3, active optical element 24 iscircular.

Number of Pixels

The number of pixels is any suitable number of independently-addressablepixels. Although the active optical element comprises at least 100independently-addressable pixels, it is generally preferred that theactive optical element comprises more than 100 independently-addressablepixels, in some embodiments, at least 800, at least 1600 and even atleast 3200 individually addressable pixels.

Coverage of the Visual Field

The active optical element is physically associated with the frameand/or the lens so that at least part of the visual field of the firsteye is covered by both the lens and the active optical element. In someembodiments, the visual field of the active optical element is the samesize as that of the lens, so the part of the visual field of the firsteye that is covered by both the lens and the active optical element isthe same, as in device 10 depicted in FIGS. 1A-1C. In some alternateembodiments, the visual field of the active optical element is smallerthan that of the lens so that the part of the visual field of the firsteye that is covered by both the lens and the active lens is smaller thanthe part of the visual field of the first eye that is covered by thelens, as in device 34 depicted in FIG. 3. In some embodiments, the partof the visual field of the first eye that is covered by both the lensand the active optical element when the gaze direction of the first eyeis straight ahead is at least 20%, at least 30%, at least 40%, at least50% and even at least 60%.

In some embodiments, the visual field of the first eye is alternatelycovered by the lens and the active optical element when the gazedirection of the first eye is straight ahead. In some embodiments, thecentral visual field of the first eye is covered by the lens and therest of the visual field is alternately covered by the lens and theactive optical element when the gaze direction of the first eye isstraight ahead

Optical Property with Changeable Value

The optical property having a changeable value can be any suitableoptical property. In some embodiments, the optical property with achangeable value is selected from the group consisting of:

a property of the pixels that provides controllable optical power forthe active optical element;

light transmission of the pixels; and

both a property of the pixels that provides controllable optical powerfor the active optical element and light transmission of the pixels.

Controllable Optical Power

In some embodiments, an optical property of the pixels having achangeable value is a property of the pixels that provides controllableoptical power for the active optical element under control of thecontroller.

In such embodiments, the active optical element can be considered atunable lens which optical power can be changed by changing someproperty (e.g., index of refraction, dimensions) of the individualpixels. In some embodiments, changing optical power includes tuning theactive optical element to be a simple lens having a fixed optical powerover the entire active optical element. In some embodiments, changingoptical power includes tuning the active optical element to be a complexlens having at least two portions, each having a different opticalpower.

As noted above, the active optical element is physically associated withthe frame and/or the lens so that at least part of the visual field ofthe first eye is covered by both the lens and the active opticalelement. Light passing through the part of the visual field that iscovered by both the lens and the active optical element is refracted byboth the constant optical power of the lens and the changeable opticalpower of the active optical element.

Any suitable technology or combinations of technologies may be used toimplement such embodiments, for example, using tunable lenses similar toor identical to the described in U.S. Pat. Nos. 7,475,985; 10,036,901;10,466,391, US 2020/0003933 and references cited therein.

Changeable Light Transmission

In some embodiments, an optical property of the pixels having achangeable value is light transmission of the pixels which is changeablefor each pixel under control of the controller. Any suitable technologyor combinations of technologies can be used to implement such anembodiment, for example, that each one of the pixels comprises an LCDpixel of a prior art transparent LCD display where the degree of lighttransmission can be controlled by the controller to transmit more light(a more transparent pixel that allows high light transmission) or lesslight (a less transparent, darker, pixel that reduces lighttransmission). Suitable such active optical elements are similar todisplays available from Crystal Display Systems Ltd. Rochester, Kent,UK.

As noted above, the active optical element is physically associated withthe frame and/or the lens so that at least part of the visual field ofthe first eye is covered by both the lens and the active opticalelement. Light passing through the part of the visual field that iscovered by both the lens and the active optical element is refracted bythe optical power of the lens but the intensity of the light is alteredby the changeable light transmission of the pixels of the active opticalelement.

Both Changeable Refractivity and Light Transmission

In some embodiments, the optical property of the pixels of the activeoptical elements that are changeable are both a property of the pixelsthat provides controllable optical power for the active optical elementand light transmission. An exemplary such embodiment is device 34depicted in FIG. 3.

Controller

An optical device according to the teachings herein comprises acontroller having a digital memory configured to:

receive from the eye-tracker a determined gaze direction of the firsteye; and

at a repetition rate, to set a value for the optical property of the atleast 100 pixels of the active optical element so as to create an imagemask through which at least some of the light reaching the first eyepasses through, thereby modifying the image formed on the retina of thefirst eye, wherein the value for the optical property is based on areceived gaze direction and the optical power of the lens. In someembodiments, the optical device also comprises a pupil size determinerthat is configured to determine and report the size of the pupil of thefirst eye, and the controller is configured to receive from the pupilsize determiner a determined pupil size of the first eye and to set avalue for the optical property of the pixels also based on the receivedpupil size.

The controller is typically a computation device, general purpose orcustom, that is configured (e.g., using software, hardware, firmware, ora combination thereof) to receive a determined gaze direction, recoverparameters from the digital memory (e.g., the optical power of thelens), calculate a required image mask, and send the required commandsto the pixels of the active optical elements to create the image mask.In some embodiments, especially embodiments where the active opticalelement is considered a tunable lens, calculations of a required imagemask include optical design and/or ray tracing calculations to accountfor factors such as the optical power of the lens (especially when thelens is a refracting lens, especially a complex refracting lens) andpupil size. Any suitable optical design and/or ray tracing calculationscan be used, for example, calculations performed usingcommercially-available software such as available from Zemax LLC(Kirkland, Wash., USA).

In preferred embodiments, the controller includes at least one componentfor data exchange with other devices, for example, to allow updating ofthe controller. Such a component can include a physical port (e.g., aUSB port) or a wireless communication component, e.g., a Bluetooth®transceiver.

The optical device according to the teachings herein is preferablyconfigured to be useful for non-invasive treatment of various visionimpairments. The treatment is affected by modifying the image that isproduced on the retina of an eye which modification is done by the imagemask created using an active optical element alone or together with arefracting lens. Depending on the embodiment and the specific imagemask, the treatment can include one or more of:

-   -   preventing the development of a vision impairment;    -   slowing down, stopping and/or preventing the progression of an        extant vision impairment;    -   reducing the severity of an extant vision impairment;    -   ameliorating the negative effects of an extant vision        impairment; and    -   improving the quality of life of a subject having a vision        impairment.

-   Vision impairments that can be treated by one or more embodiments of    the teachings herein include, but are not limited to:    -   refractive errors including myopia, hyperopia and anisometropia;    -   vision impairments caused by macular degeneration; and    -   amblyopia.

As detailed hereinbelow, the image mask modifies the image formed on theretina of the first eye, thereby treating a vision impairment. Inembodiments where the lens is a plano lens, the image mask alonemodifies the image formed on the retina. In alternative embodimentswhere the lens is a refracting lens having a non-zero-optical power, theimage mask and the lens operate together to modify the image formed onthe retina.

In some embodiments, the controller is configured to create an imagemask having a portion that amplifies an image modification done by acorresponding lens, for example, to increase the magnitude of theoptical power of a portion of the lens that has optical power.

In some embodiments, the controller is configured to create an imagemask having a portion that decreases an image modification done by acorresponding lens, for example, to decrease the optical power of aportion of the lens that has a positive optical power, or to decreasethe optical power of a portion of the lens that has a negative opticalpower. For example, in some embodiments the lens is configured todegrade at least a portion of the visual field of the eye by blurring aportion of an image formed on the retina to achieve a therapeutic effectand in some such embodiments, an image mask is created to counter aportion of the blurring by sharpening some of the image. In anotherexample, in some embodiments the lens is configured to sharpen a portionof an image formed on the retina to achieve a therapeutic effect and insome such embodiments, an image mask is created to counter a portion ofthe sharpening by blurring some of the image.

In preferred embodiments, as discussed in greater detail below, themodification of an image that is formed on the retina of an eye by anactive optical element (and, in some embodiments, also an associatedrefracting lens) leads to degradation of at least part of the image.Accordingly, in some embodiments, the controller, the lens and theactive optical element are together configured so that during operationof the optical device, at least a portion of the visual field of thefirst eye is degraded by the optical power of the lens and/or by theimage mask. In some embodiments, the created image mask is such that themodifying of the image formed on the retina of the first eye is suchthat at least some of the image is degraded. In some embodiments, wherethe lens is a refracting lens that is configured to degrade at least aportion of the visual field of the first eye of the subject, the createdimage mask is such that the modifying of the image formed on the retinaof the first eye counters at least some of the degradation caused by thefirst lens.

In some embodiments, the image mask is created in such a way so that theimage formed on the retina is a therapeutic image which is configured toaffect a persistent change in how the brain perceives input from the eyeand/or to stimulate an actual physical change in the eye itself asopposed to simply providing an instantaneous better image. Suchpersistent changes include:

-   -   effecting physical eyeball growth to prevent development or stop        the progression of myopia;    -   encouraging the development of a persistent pseudofovea to        alleviate vision loss due to macular degeneration; and    -   encouraging the use of an amblyopic eye over a non-amblyopic eye        to cause a persistent change in the way the brain perceives        images received from the amblyopic eye to improve the visual        deficits of the amblyopic eye and to improve binocularity.

A controller is configured to calculate a required image mask based onthe determined gaze direction of the first eye received from the eyetracker; the optical power of the lens, and in some embodiments also thedetermined pupil size of the first eye received from the pupil sizedeterminer. The controller then creates a calculated image mask patternusing the active optical element by setting a value for the changeableoptical property of the pixels of the active optical element. Therequired image mask that is calculated and created by the controller isan image mask through which at least some of the light reaching thefirst eye passes, modifying the image formed on the retina of the firsteye. The modified image providing the desired treatment.

In preferred embodiments, the modification of the image falling on theretina is constant in the frame of reference of the eye, that is to say,the modification of the image moves according to the gaze direction ofthe eye. For example, in an exemplary embodiment the controller createsa mask that ensures that light that reaches the fovea of the eye of thesubject is always focused. In such an example, at each moment in timethe properties of the pixels of the active optical element are set sothat the instantaneously-formed optical mask, together with the lens,focus light on the fovea. To an external observer it seems that the sameimage mask is moving on the active optical element in coordination withthe gaze direction as the eye moves, so that the image mask ismaintained at the same position relative to the gaze direction of thefirst eye.

Accordingly, in preferred embodiments, two succeeding image masks (twoimage masks where one is created immediately after the other) createdbased on two respective received gaze directions are created so that themodifying of an image formed on the retina of the first eye by the twosucceeding images is substantially the same. In this context,“substantially the same” means that two succeeding image masks aresufficiently similar or identical to provide the same treatment for theeye.

In embodiments where the lens is a plano lens, the modification of lightreaching the first eye is exclusively due to the image mask. Inembodiments, where the lens is a simple refracting lens having a singlefocal optical power over the entire lens, the modification of lightreaching the first eye is a combination of the effect of the image maskand the lens. In some such embodiments, the controller can be consideredas moving the same mask on the active optical element so thatsubstantive portions of the mask are always positioned in the sameposition relative to the gaze direction (and fovea) of the eye. Thus, insome embodiments where the lens is a plano lens or where the lens is asimple refracting lens having a single focal optical power over theentire lens, two succeeding image masks created based on two respectivereceived gaze directions are substantially the same relative to therespective gaze directions, so that the two succeeding image masks arepositioned at a constant location relative to the gaze direction of thefirst eye.

In embodiments where the lens is a complex refracting lens having atleast two portions, each having a different optical power, themodification of light reaching the first eye is a combination of theeffect of the image mask and the lens. In some such embodiments, thecontroller creates the optical mask so that modification of the imagethat reaches the retina remains the same, which requires that each maskbe created accounting also for the optical power of the lens relative tothe gaze direction. In such embodiments, two succeeding mask may besubstantially different, for example, in a situation where an earliermask is created when the gaze direction is directed through a portion ofthe lens having a first optical power and the succeeding mask is createdwhen the gaze direction is directed through a portion of the lens havinga second, substantially different, optical power. Thus, in someembodiments where the lens is a complex refracting lens having at leasttwo portions, each having a different optical power, two succeedingimage masks created based on two respective received gaze directions aresuch that the modification of an image that reaches the retina remainsthe same.

In some embodiments, an additional factor that is accounted for by thecontroller when calculating a required image mask is pupil size. As isknown to a person having ordinary skill in the art, the size of anoptical aperture influences the image formed on a given image plane. Inthe context of the teachings herein, the pupil size (the aperture) whichvaries, inter alia, as a result of ambient illumination conditions,vergence or distance to a viewed object influences the image formed onthe retina (the image plane). Accordingly, in preferred embodiments, thecontroller also accounts for the pupil size when calculating andcreating an image mask so that two succeeding image masks created basedon two respective received pupil sizes are such that the modification ofan image that reaches the retina remains the same.

Other Parameters

In some embodiments parameters other than a determined gaze direction,lens optical power and pupil size are used by the controller to createan image mask. The other parameters can be stored parameters and/ormeasured parameters and are discussed in greater detail below.

Parameters stored by the controller and used to create an image mask caninclude none, one or more of:

-   -   one or more image mask designs suitable for treatment of one or        more conditions or different stages of the same treatment;    -   formulae to calculate a required mask;    -   clinical data of the subject intended to use the optical device        (e.g., vision of one or both eyes, including visual acuity,        refraction values of the eyes, ethnicity, age, map of retinal        damage, retinal curvature, axial length, interpupillary        distance);    -   optical power and other parameters of an optical device such as        contact lens worn by the subject concurrently with wearing the        optical device; and    -   optical parameters of the lens (e.g., refraction distribution,        prism aberrations),

In some embodiments, the controller creates an image mask also toaccount for aberrations in the lens. For example, when the gazedirection of an eye is directed far from the lens optical power center(i.e., at a non-zero angle from straight ahead), light reaching theretina of the eye passes through lens aberrations which, in someembodiments, are compensated by the created image mask.

Parameters that are be measured, reported to the controller and used bythe controller to create an image mask can include none, one or more of:

-   -   distance of the optical device from the user (Such embodiments        typically include a distance determiner to determine distance of        the optical device to a user and report to the controller. In        some embodiments, the distance determiner is a separate        distance-determining component (e.g., based on parallax, laser        distance measurement, ultrasonic distance measurement). In some        embodiments, the eye tracker is configured to also function as a        distance determiner. In some embodiments, the controller is        configured to calculate the distance of the optical device to        the user from data provided by the eye tracker);    -   ambient illumination (Such embodiments typically include an        ambient light intensity sensor to determine the intensity of        ambient light and report to the controller. In some embodiments,        the ambient light sensor is a separate light sensor component        (e.g., based on a camera or photocell). In some embodiments, the        eye tracker is configured to also function as an ambient light        intensity sensor. In some embodiments, the controller is        configured to calculate the ambient light intensity from data        provided by the eye tracker);    -   vergence (Such embodiments typically include a vergence sensor        to determine the vergence of the eyes and report to the        controller. In some embodiments, the vergence sensor is a        separate vergence sensing component (e.g., based on a camera).        In some embodiments, the eye tracker is configured to also        function as a vergence sensor. In some embodiments, the        controller is configured to calculate the vergence from data        provided by the eye tracker. In some embodiments, a measured        vergence is used to calculate the viewing distance to an object        that is being viewed); and    -   range to a viewed object (Such embodiments typically include a        range determiner to determine the range to an object viewed by        the user and report to the controller. In some embodiments, the        range determiner is a separate range-determining component        (e.g., based on a camera (e.g., using parallax), laser        rangefinder, ultrasound rangefinder).

In some embodiments, the controller is configured to create a given maskor a type of mask continuously, whenever the optical device is worn bythe user. Additionally or alternatively, in some embodiments, thecontroller is configured to create a given mask or type of mask for aspecific treatment for a limited time. In some embodiments, atime-limited treatment is environment-based, e.g., activated whenreading (for example, by user selection or detection of range to anobject viewed), activated when outside (for example, by user selection,detection of range to an object viewed), activated under specific lightconditions (light or dark, for example, as detected by a light sensor).Additionally or alternatively, in some embodiments, a time-limitedtreatment is based on a schedule (e.g., based on clinical considerationsas determined by a health-care professional, for example, one hour aday, 5 minutes an hour). Additionally or alternatively, in someembodiments the controller is configured to create a given mask or atype of mask for a specific treatment for a limited time based on theamount of power available in an associated power supply.

Modifying an image formed on the retina of an eye to treat a visionimpairment has been disclosed previously but the optical deviceaccording to the teachings herein provides improvement to the state ofthe art. Depending on the specific embodiment, one or more advantages ofthe device according to the teachings herein include: no need for thesubject to move the head to look at an object because the movement ofthe eyes relative to the head is compensated for by the active opticalcomponent; optical corrections can be changed according to momentary ortemporary conditions such as pupil size, range to target, convergence;intensity of treatment can be adjusted with progress; there is automaticcompensation for misalignments that occur in the production process orby how the subject wears the device; and potentially, a subject can wearthe same device to treat amblyopia at a young age and myopia at a laterage.

U.S. Pat. No. 7,832,859, US 2012-0113386 and U.S. Pat. No. 8,899,746 allteach contact lenses that modify the image formed in the retina of aneye for preventing and/or reducing the progression of myopia and/orhyperopia. Unlike such contact lenses, the teachings herein maintain theimage-modifying element (the image mask created using the active opticalelement, in some embodiments also the lens) at a distance of not lessthan 5 mm and not more than 50 mm from the surface of the cornea offirst eye. As can be demonstrated using ray tracing lens simulations,the retinal image formed by light passing through an image mask that isat a distance from the cornea is qualitatively different from theretinal image formed by light passing through a contact lens asdescribed above.

Further, compared to such contact lenses, some embodiments of theoptical device according to the teachings herein provides improvedseparation between central and peripheral images due to the distinctdistance of the frame from the eye compared to contact lens positionwhich is in contact with the cornea of the eye. The optical device isexpected to achieve greater compliance as children might tend to rejectinsertion of a contact lens to the eye. Unlike the contact lens theoptical element pattern can be dynamically adjusted according to changessuch as in pupil size and viewing distance. Such contact lenses cannotcompensate for different pupil sizes in contrary to the image formed onthe retina by the optical element which qualitatively changes with pupilsize while in preferred embodiments. Further, unlike an image maskcreated using an optical device according to the teachings herein, aretinal image formed by light passing through a contact lens changes asthe contact lens moves relative to the cornea of the eye. Further, it isknown in the art that wearing contact lenses might be uncomfortable andfrightening for children, thereby lowering compliance. In addition,contact lens wear may cause eye infection and the natural movements ofthe contact lenses over the cornea of an eye might reduce treatmentefficacy.

WO 2018/055618 to the Applicant teaches treatment of amblyopia of asubject having an amblyopic eye and a non-amblyopic eye by displaying ona display screen a modified image to the non-amblyopic eye,specifically, an image having low-quality portions to encourage use ofthe amblyopic eye. US 2019/0200858 to the Applicant teaches display ofan image on a display screen to the eye of a subject suffering frommacular vision damage to treat the eye. Both WO 2018/055618 and US2019/0200585 teach a wearable vision aid based on a virtual realitydevice that includes a camera to acquire an image of the surroundings, aprocessor to modify an acquired image, and a display screen to displaythe modified image to the eye, the former to treat amblyopia the latterto treat macular vision damage. Such virtual reality devices isolate theuser from the outside world which can be challenging for young children.In addition, the recommended age for using virtual reality devices is 12years while treatment for amblyopia should start as early as possible inlife. Importantly, such virtual reality devices are known to causenausea, discomfort and distress after short period of time, so cannot beused continuously for a long period of time to treat children.

Eye Tracker and Mask Refresh Rate

An optical device according to the teachings herein comprises an eyetracker configured to determine and report the gaze direction of thefirst eye. Any suitable eye tracker can be used, for example, an eyetracker by Tobii AB (Danderyd, Sweden).

The eye tracker is configured to determine and report the gaze directionof the first eye (and, in some embodiments, the location of the eyesrelative to the optical device and in some embodiments also the pupilsize, see below) at any suitable rate. The controller receives thedetermined gaze direction and creates an image mask at any suitablerate.

In some embodiments, the eye-tracker is configured to determine andreport the gaze direction of the first eye (and, in some embodiments,the location of the eyes relative to the optical device and/or in someembodiments also the pupil size) to the controller at a rate of notslower than 1 Hz; and the controller is configured to create a new imagemask based on a received gaze direction at a repetition rate of notslower than 1 Hz. In preferred embodiments, the rate of determining isfaster than 1 Hz, e.g., in some embodiments not slower than 2 Hz, notslower than 4 Hz, not slower than 8 Hz, not slower than 12 Hz, notslower than 20 Hz and even not slower than 30 Hz. In preferredembodiments, the repetition rate of creating an image mask is fasterthan 1 Hz, e.g., in some embodiments not slower than 2 Hz, not slowerthan 4 Hz, not slower than 8 Hz, not slower than 12 Hz, not slower than20 Hz and even not slower than 30 Hz.

Pupil Size Determiner

In some embodiments, a pupil size determiner comprises a pupil sizedeterminer configured to determine and report the pupil size of thefirst eye. Any suitable pupil size determiner can be used. Although insome embodiments a pupil-size determiner is a separate component, inpreferred embodiments the eye tracker is also the pupil size determineras most commercially-available eye trackers report pupil sizeconcurrently with gaze direction.

In FIGS. 1B and 1C, optical device 10 comprises an eye tracker 26 thatalso functions as a pupil-size determiner, being configured to determineand report both gaze direction and pupil size of first eye 22 a.

In FIG. 3, optical device 34 comprises an eye tracker 26 that isconfigured to determine and report gaze direction of a first eye and aseparate pupil size determiner 36 that is configured to determine andreport the pupil size of a first eye.

The pupil size determiner is configured to determine and report thepupil size of the first eye at any suitable rate. The controllerreceives the determined pupil size and creates an image mask also basedon the received pupil size. Typically, but not necessarily, the pupilsize determiner reports the pupil size at the same rate as the eyetracker reports the gaze direction.

In some embodiments of the optical device having an active opticalelement with changeable light transmission values for the pixels,especially some embodiments configured for treating anisocoria where thetwo pupils of the subject are of unequal size, the controller isconfigured to change the light transmission through one or two activeoptical elements to balance the intensity of light reaching the twoeyes.

Second Lens

In the above description, some of the components of a wearable opticaldevice according to the teachings herein that are discussed are atransparent lens, a wearable frame to maintain the lens in front of afirst eye of the subject and a transparent pixelated active opticalelement physically associated the frame and/or lens so that at leastpart of the visual field of the first eye is covered by both the lensand the active optical element.

In some embodiments, the optical device is monocular, and the opticaldevice does not comprise an optical component that is maintained infront of the second eye of the subject. In device 10 depicted in FIGS.1A-1C and device 34 depicted in FIG. 3, there is a component indicatedwith 38. When component 38 is empty (that is to say, is absent or isopaque), the optical device is a monocular optical device.

In some embodiments, the transparent lens of the optical devicediscussed above is a first lens of the optical device, and the opticaldevice further comprises:

a second transparent lens, a distal surface and a proximal surface;

-   the wearable frame configured, when worn by the subject, to maintain    the proximal surface of the second lens in front of the second eye    of the subject at a distance of not less than 5 mm and not more than    50 mm from the surface of the cornea of the second eye so that at    least part of the visual field of the second eye is covered by the    second lens when the gaze direction of the second eye is straight    ahead.

In some embodiments of optical device 10 depicted in FIGS. 1A-1C andoptical device 34 depicted in FIG. 3, lens 12 is a first lens, and theoptical device comprises a second transparent lens 38 having a distalsurface 40 and a proximal surface 42; wearable frame 18 is configured,when worn by the subject, to maintain proximal surface 42 in front of asecond eye 22 b of subject 20 at a distance 44 of not less than 5 mm andnot more than 50 mm from the surface of the cornea of second eye 22 b sothat at least part of the visual field of second eye 22 b is covered bysecond lens 38 when the gaze direction of second eye 22 b is straightahead.

In some embodiments, the second lens is a plano lens. Alternatively, insome embodiments the second lens is a refracting lens having a non-zerooptical power. In preferred embodiments, the second lens is configuredto at least partially correct refractive errors of the second eye of thesubject for which the optical device is intended.

The second lens is any suitable size. In some embodiments, the frame andthe second lens are together configured so that at least 30% of thevisual field of the second eye is covered by the second lens when thegaze direction of the second eye is straight ahead. In some embodiments,at least 40%, at least 50%, at least 60% and even at least 70% of thevisual field of the second eye is covered by the second lens when thegaze direction to the second eye is straight ahead.

Tracking of Second Eye

In some embodiments, the optical device further comprises an eye trackerconfigured to determine the gaze direction of the second eye and toreport a determined gaze direction to the controller. In some suchembodiments, the eye tracker for determining the gaze direction of thefirst eye is also configured to determine and report the gaze directionof the second eye. In some embodiments, the optical device comprises asecond eye tracker to determine and report the gaze direction of thesecond eye, the second eye tracker different from the eye tracker thatis configured to determine and report the gaze direction of the firsteye. In some such embodiments, the controller is configured to createthe image mask for the first eye also based on the reported gazedirection of the second eye. In FIGS. 1A-1C, optical device 10 includesa second eye tracker 46 configured to determine and report the gazedirection of second eye 22 b to controller 28.

Second Active Optical Element

In some embodiments, the transparent pixelated active optical element ofthe optical device discussed above is a first transparent pixelatedactive optical element of the optical device, and the optical devicefurther comprises:

-   -   a second transparent pixelated active optical element comprising        at least 100 independently-addressable pixels, each one of the        pixels having an optical property with a changeable value, the        second active optical element physically associated with the        frame and/or the second lens so that at least part of the visual        field of the second eye is covered by both the second lens and        the second active optical element, and

-   wherein the controller is further configured to:    -   iii. at a repetition rate, set a value for the optical property        of the at least 100 pixels of the second active optical element        so as to create an image mask through which at least some of the        light reaching the second eye passes through, thereby modifying        the image formed on the retina of the second eye,

-   wherein the value for the optical property is based on a gaze    direction of the second eye and the optical power of the second    lens.

FIGS. 4A, 4B and 4C depict an additional embodiment of an optical deviceaccording to the teachings herein, optical device 48. The like-numberedcomponents of optical device 48 are substantially identical to thecomponents of optical device 10 depicted in FIGS. 1A-1C. Optical device48 further comprises a second transparent pixelated active opticalelement 50 comprising at least 100 independently-addressable pixels,each one of the pixels having an optical property with a changeablevalue, second active optical element 50 physically associated with frame18 and/or second lens 38 so that at least part of the visual field ofsecond eye 22 b is covered by both second lens 38 and second activeoptical element 50.

In some embodiments, the gaze direction of the second eye used by thecontroller is an estimated gaze direction, e.g., the controllerestimates the gaze direction of the second eye on the gaze direction ofthe first eye and, optionally, other parameters such as distance to aviewed object. In some embodiments, the gaze direction of the second eyeused by the controller is a determined and reported by an eye tracker,and the controller receives the determined gaze direction of the secondeye.

In some embodiments, the repetition rate of setting the values for thepixels of the first active optical element and the second active opticalelement are different. In preferred embodiments, the repetition ratesare the same.

The details and variants of a second lens are the same as recited abovefor a first lens. The details and variants of a second transparentpixelated active optical element are the same as recited above for thefirst transparent pixelated active optical element. The details andvariants of a second eye tracker are the same as recited above for thefirst eye tracker. The operation of the controller with regards to thesecond transparent pixelated active optical element is the same asrecited above for the first active transparent pixelated active opticalelement. For reasons of brevity, all these details and variants are notrepeated here, but the above recitations relating to the componentsdesignated as being “first” provide literal support for all the aboveoptions for the like components designated as being “second”.

The teachings herein can be used for the non-invasive treatment ofdifferent vision impairments. Typically, a specific optical device isconfigured for treatment of one or more specific vision impairments of aspecific subject. In some embodiments, such configuration comprisesuploading data and/or parameters and/or treatment protocols to thecontroller. Additionally or alternatively, in some embodiments suchconfiguration comprises configuring specific physical features of theoptical device, for example, the optical power of one or two lenses (12and 38 in the Figures). For some vision impairments, a monocularembodiment of the optical device is sufficient or preferred. For somevision impairments, a binocular embodiment of the optical device isessential or preferred. A person having ordinary skill in the art isable, upon perusal of the specification and figures, to perform therequired configurations without resorting to undue experimentation.

The configuration and use of the device for treatment of some specificvision impairments and implementation of methods for treating somespecific vision impairments is discussed below.

Refractive Errors

The eye of a full-term human baby is about 1.8 cm long (from the face ofthe cornea to back of the eye). The eye grows throughout childhood,reaching a length of about 2.5 cm in adulthood where ideally the eyereaches the state of emmetropia where there is a match between the powerof the optics of the eye and the axial length of the eye so that in theabsence of accommodation, distant images are focused at thephotoreceptor layer of the retina.

Emmetropization is the process of achieving emmetropia and involves areduction in the refractive error that is present at birth, caused bythe mismatch between the power of the optics of the eyes and the axiallength of the eye. Typically, the refractive state of the eye of anewborn eye is hyperopic (the focal point is beyond the retina) and overtime becomes emmetropic. In some instances, the ocular components of theeye, notably the lens and cornea, continue to change and eye growthoccurs beyond the time that initial emmetropia is obtained, and the eyebecomes myopic (the focal point of the eye is before the retina). It isundisputed that growth of the eye to achieve emmetropization involvesvisual feedback which is apparently why children who spend prolongedperiods of time looking at nearby objects such as books, computerscreens and telephone screens often become myopic. The prevalence ofmyopia is nearly 40% among adults in the United States, and up to 80percent of young adults in China. Long-term risks associated with highmyopia progression include cataracts and retinal detachment.

Clinical observations provide support for the idea that visual signalsfrom the peripheral retina can have a significant impact onemmetropization at the fovea and possibly the genesis of commonrefractive errors.

In U.S. Pat. No. 7,832,859; WO 2010/129466 and WO 2011/049642 aredisclosed contact lenses having at least two concentric zones. Thecircular central zone is configured to correct for the myopia of the eyeof a subject, providing a sharp focused image to the central visualfield of retina. A first concentric annular zone around the central zoneprovides a myopic defocused image that overlaps the sharp focused image.In some embodiments, additional even-numbered concentric annular zonesenhance the sharp focused image of the central zone and additionalodd-numbered annular zones enhance the myopic defocused image. U.S. Pat.No. 7,832,859 presents clinical data demonstrating that wearing acontact lens for a several months with simultaneously provides twoconcentrically-overlapping images at the central visual field of theeye, a sharp focused image and a myopic defocused image, slowing theaxial growth on the eye and slowing down the myopia progression. This isattributed to the effect the defocused image has on the axial eyegrowth. U.S. Pat. No. 7,7666,478 describes other type of contact lenswith a focused and a defocused image presented to the eye.

In some embodiments, an optical device according to the teachings hereinis configured to treat refractive errors such as myopia of one or botheyes of a subject in a manner that is analogous to that described in theart.

It is important to note that, although in some embodiments only a singleeye is treated, usually both eyes are treated simultaneously, for eacheye the optical device comprises a lens and an associated active opticalelement. For clarity and brevity, the following description relates toan optical device including a lens and associated active optical elementfor treating refractive errors of an eye. It is understood that when anoptical device includes a single lens and associated active opticalelement, the description refers to a lens and active optical elementphysically associated with the frame of the optical device so that atleast part of the visual field of the first eye is covered by both thelens and the active optical element. It is also understood that when anoptical device includes two lenses and two respective associated activeoptical elements, the description refers to and provides literal supportfor both the first lens and the associated first active optical elementphysically associated with the frame of the optical device so that atleast part of the visual field of the first eye is covered by both thefirst lens and the first active optical element and to the second lensand the associated second active optical element physically associatedwith the frame of the optical device so that at least part of the visualfield of the second eye is covered by both the second lens and thesecond active optical element.

In embodiments of an optical device configured to treat refractiveerrors of an eye of a subject, the controller, lens and active opticalelement are configured so that during operation of the optical device,the lens and a created mask together simultaneously provide twoconcentrically-overlapping images to the central visual field of thefirst eye: a sharp focused image and a myopic defocused image, similarto discussed in the above-referenced art. In some embodiments, thecreated image mask comprises at least two distinct regions, a centralfirst region configured to provide a sharp focused image and a secondregion surrounding the first region configured to provide a myopicdefocused image. Creation of the mask is based on the received gazedirection to ensure that the two images concentrically-overlap and arelocated at the center of the visual field of the retina of the eye. As aresult, the subject wearing the optical device perceives a sharp focusedimage together with a “halo” (the myopic defocused image), the halobeing the portion of the visual field of the eye that is degraded by theoptical power of the lens and/or by the created image mask. The relativeand absolute size of the two regions of the image mask is determined,inter alia, by the desired relative intensity of the provided sharpfocused image and myopic blurred image: increasing the area of a regionof the image mask responsible for providing one of the images relativeto the area of the other region increases the relative intensity of thatimage. Accordingly, changing the relative and absolute areas of theregions allows fine tuning the intensity of the treatment and forprogressively adjusting the treatment. Similarly, in some embodimentschanging the optical power of the regions allows fine tuning theintensity of the treatment and for progressively adjusting thetreatment.

In preferred embodiments, the controller creates the image mask alsobased on the pupil size received from a pupil size determiner. In someembodiments where the image mask comprises at least two portions, acentral first region and a second region surrounding the first region,the absolute and relative sizes of the two regions of the image mask aredependent on the determined pupil size, for example larger the pupil thelarger the central first region is. Further, as is known in the art, allother things being equal, a larger pupil size reduces the sharpness ofan image formed on the retina of an eye when compared to a smaller pupilsize. Accordingly, in some preferred embodiments the pupil size alsoinfluences the optical power of central first region of the image maskto ensure that the sharp focused image is sharp and focused.Accordingly, in some preferred embodiments the pupil size alsoinfluences the optical power of peripheral second region to ensure thatthe defocused image is defocused enough to enable myopia control. Pupilsize is known to change for various reasons including ambient lightconditions, vergence and viewing distance.

Some specific embodiments of the teachings herein suitable for treatingrefractive errors are discussed below.

In some embodiments, the controller is configured to create an imagemask including at least two regions, a central first region forproviding the sharp focused image and a second region surrounding thefirst region for providing the myopic defocused image. In FIGS. 5A (gazedirection is straight ahead) and 5B (gaze direction to the left) aredepicted a portion of an optical device similar or identical to device48 depicted in FIGS. 4A-4C in a view from the back towards the proximalside having a first lens 12 and an associated first active opticalelement 24, depicted with already-created image mask 52 Image mask 52has three regions:

a circular central first region 52 a for providing a sharply focusedimage to an eye;

a second region 52 b for degrading a portion of the visual field offirst eye 22 a to provide the desired myopic defocused image; and

a third region 52 c that makes up the balance of the pixels of firstactive optical element 24. In some embodiments where lens 12 is anoptimal corrective lense, first region 52 a can be set to have nooptical power.

Controllable Optical Power

In some such embodiments, lens 12 is a plano lens and an opticalproperty with a changeable value is a property of the pixels thatprovides controllable optical power for the active optical element,optionally also with changeable light transmission. In such embodiments,the pixels of first region 52 a are set so that first region 52 aconstitutes a lens having an optical power to provide a sharp focusedimage while the pixels of second region 52 b are set to some othervalue, thereby providing a lens having an optical power that provides amyopic defocused image.

In some such embodiments, lens 12 is a refracting lens and an opticalproperty with a changeable value is a property of the pixels thatprovides controllable optical power for the active optical element,optionally also with changeable light transmission. In preferred suchembodiments, the refracting lens (whether simple or complex) ispreferably configured as known in the art of ophthalmology to correctthe refractive errors of the eye. In such embodiments, the pixels offirst region 52 a are set so that first region 52 a constitutes a lenshaving an optical power to provide a sharp focused image (in someinstances focusing in addition to the focusing attributable to theoptical power of the lens and in some embodiments, where the lens hassufficient optical power, first region 52 a constitutes a plano lens,optionally correcting for aberrations in lens 12). In such embodiments,the pixels of second region 52 b are set to some other value, therebyproviding a lens having an optical power that provides a myopicdefocused image, typically requiring neutralization of the correctionprovided by the optical power of lens 12. Thus, in some suchembodiments, refracting lens 12 is configured to correct refractiveerrors of the eye and first region 52 a of image mask 52 operatestogether with refracting lens 12 to improve a respective portion of thevisual field (to provide a sharp focused image) while second region 52 bof image mask 52 counters at least some of the improvement provided byrefracting lens 12 to degrade a respective portion of the visual field(to provide a myopic defocused image).

Alternatively, in some such embodiments, refracting lens 12 isconfigured to degrade the visual field of the eye and first region 52 aof image mask 52 counters refracting lens 12 by improving the respectiveportion of the visual field (to provide a sharp focused image) whilesecond region 52 b of image mask 52 operates together with refractinglens 12 to degrade the respective portion of the visual field (toprovide a myopic defocused image).

Similarity Between Two Image Masks

In FIG. 5A, first region 52 a is circular and second region 52 b isannular and concentric with first region 52 a. In FIG. 5B, first regionis circular and second region 52 b is almost annular as the top portionof second region 52 b is truncated by the border of first active opticalelement 24.

In some embodiments, refractive lens 12 is a complex lens having atleast two portions, each such portion of the lens having a differentoptical power. In such embodiments, a created image mask 52 is complexas the values of the changeable property of the pixels must account forthe optical power of the portion of the lens that is directly associatedwith each pixel. Accordingly, in embodiments where refracting lens is acomplex lens the image masks 52 in FIGS. 5A and 5B are in realitydifferent.

In some embodiments, the controller also creates the two image masks 52to correct for aberrations in lens 12: in such embodiments, a furtherdifference between the two image masks 52 is the differences that arerequired to correct for the lens aberrations.

In some such embodiments, a further difference between the two imagemasks 52 are differences dictated by different pupil size that can occurdue to a different vergence or different range to an observed object.

Despite such differences as listed above, the two image masks 52depicted in FIGS. 5A and 5B are considered substantially identical asthe therapeutic effect of the combined optical powers of lens 12 and therespective image masks 52 is the same relative to the gaze direction ofeye 22 a.

In the embodiments discussed above suitable for treating refractiveerrors, the created image mask comprises at least two distinct regions,a central first region configured to provide a sharp focused image and asecond region surrounding the first region configured to provide amyopic defocused image, where the absolute and relative sizes of the tworegions are preferably dependent on a determined pupil size. In someembodiments, the image mask comprises further regions configured toeither enhance the sharp focused image provided by the first region orto enhance the myopic defocused image provided by the second region.Typically, such further regions are each in the form of a ring thatsurrounds a preceding ring and is configured to enhance the one of thetwo images different from the image enhanced by the preceding ring. Forexample, in some embodiments the image mask comprises a third regionthat surrounds the second region and is configured to enhance the sharpfocused image provided by the first region. For example, in someembodiments the image mask comprises a fourth region that surrounds thethird region and is configured to enhance the myopic defocused imageprovided by the second region.

Amblyopia

Amblyopia is a vision defect where the two images perceived from the twoeyes are so different that the brain cannot fuse them into one unitedimage. When the two images from the two eyes cannot be fused, confusionoccurs. In order to avoid the confusion, the brain tends to ignore oneof the two images, usually the one with the lower contrast or the oneprovided from an eye with deviating gaze direction, and amblyopiaoccurs. The brain uses the image perceived from the non-amblyopic eye,the amblyopic eye suffers from lower visual acuity and, as a result, thesubject primarily sees with the non-amblyopic eye and loses at leastsome of the binocular vision. WO 2018/055618 and U.S. Pat. No.10,251,546 teach that by displaying a poor-quality image to the centralvision of the non-amblyopic eye, the brain can be trained to use theamblyopic eye, thereby improving the visual performance of that eye suchas the visual acuity of the amblyopic eye and binocular vision.

For treatment of amblyopia in a subject according to the teachingsherein, either a monocular or binocular optical device is provided.

In embodiments where a monocular optical device is used, an image maskis created using the active optical element to degrade the vision of thenon-amblyopic eye in a manner analogous to the teachings of WO2018/055618 and U.S. Pat. No. 10,251,546.

In embodiments where a binocular optical device is used, a mask iscreated using the first active optical element to degrade the vision ofthe non-amblyopic eye in a manner analogous to the teachings of WO2018/055618 and U.S. Pat. No. 10,251,546 and a second lens and/or secondactive optical element is optionally used to improve the vision of theamblyopic eye.

(First) Active Optical Element for the Non-Amblyopic Eye

WO 2018/055618 and U.S. Pat. No. 10,251,546 teach that it isadvantageous to display an image to the non-amblyopic eye of a personsuffering from amblyopia where the portion of the image that is seen bythe central vision of the non-amblyopic eye is blurred to a degree (interms of size of the degraded portion and level of degradation)sufficient to reduce inter-ocular suppression, thereby allowing thevisual system to activate the amblyopic eye and enable using the twoeyes simultaneously, so that the brain perceives the images receivedfrom both eye. At the same time, it is preferable to keep the peripheralportions of the image that are seen by the non-central vision of thenon-amblyopic eye less degraded or not at all degraded, therebyassisting the fusion of the images by the brain and enhancing complianceas a large part of the non amblyopic eye image is sharp.

In some embodiments of the teachings herein suitable for the treatmentof amblyopia, the (first) active optical element and the controller ofthe vision are together configured to create an image mask that dividesthe (first) active optical element into two different zones:

-   -   a first central zone corresponding to a central portion of the        visual field of the non-amblyopic eye; and    -   a second zone surrounding the first central zone corresponding        to a non-central portion of the visual field of the        non-amblyopic eye;

-   wherein:

-   the first central zone is configured for degraded passage of light    therethrough; and

-   the second zone is configured for passage of light therethrough that    is better than the degraded passage through the first central zone.

In some embodiments, the first central zone covers at least 2% of thecentral visual field of the eye, the central visual field of thenon-amblyopic eye corresponding to the foveal visual field havingangular dimensions of 4°-6°. In some embodiments, the first central zonecovers at least 20%, at least 30%, at least 40%, at least 60%, at least80% of the central visual field of the amblyopic eye.

In some embodiments, the second zone has an angular dimension of atleast 2° around the first central zone. In some embodiments, the secondzone covers the balance of the active optical element.

In some embodiments suitable for treating amblyopia, the (first) lensfor the non-amblyopic eye is a plano lens which primary purpose issupporting the (first) active optical element in the correctionposition. In preferred embodiments suitable for treating amblyopia, the(first) lens for the non-amblyopic eye is a refracting lens. In suchembodiments, any suitable refracting lens is used, preferably forcorrecting vision defects of the non-amblyopic eye as is known in theart of ophthalmology.

In embodiments the optical property with a changeable value is aproperty of the pixels that provides controllable optical power for the(first) active optical element. the configuration of the first centralzone for degraded passage of light therethrough comprises, and in someembodiments consists of, the controller setting the pixels correspondingto the first central zone so that the light passing through the firstcentral zone is less focused on portions of the retina than lightpassing through the second zone, so that light passing through the firstcentral zone produces a less focused (and thereby degraded) image on theretina than the second zone.

In embodiments where a changeable optical property of the pixels of the(first) active optical element is the degree of transmission of light,in some embodiments the configuration of the first central zone fordegraded passage of light therethrough comprises, and in someembodiments consists of, the controller setting the pixels correspondingto the first central zone to a lower light transmission than pixelscorresponding to the second zone.

In embodiments where the changeable optical property is both of thementioned above, either or both of the above image mask configurationscan be used.

Amblyopic Eye

As noted above, according to an embodiment of the teachings hereinsuitable for the treatment of amblyopia, the vision of the amblyopic eyeis preferably either left unaffected or is improved. When a monocularoptical device is used, the vision of the amblyopic eye is leftunaffected. When a binocular optical device is used, the vision ofamblyopic eye is optionally improved using a second refracting lens, asecond active optical element, or a second refracting lens together witha second active optical element.

Thus, in some embodiments, no or a non-corrective second lens isprovided for the amblyopic eye.

In preferred embodiments, a second refracting lens is provided for theamblyopic eye, configured to correct the vision of the amblyopic eye inthe usual way as is known to a person skilled in ophthalmology,preferably optimal correction, to allow improved vision by the amblyopiceye.

In preferred embodiments, the amblyopic eye is not provided with asecond active optical element associated with the second lens.

In some embodiments, the amblyopic eye is provided with a second activeoptical element, e.g., for correcting aberrations in a corrective(second) lens and/or to increase the optical power of the second lenswhen needed.

Amblyopia with microtropia is a vision impairment where the gazedirections of the two eyes deviate one from the other at a small angleof deviation, typically below 8 prism diopters. To compensate for thisdeviation, the amblyopic eye develops a “preferred retinal location” inthe parafovea of the retina which acquires images. In some embodimentswhere a binocular optical device is configured to treat amblyopia withmicrotropia, in addition to using a first active optical element toblur/block the central visual field of the non-amblyopic first eye asdescribed above, the controller is configured to create an image maskusing a second active optical element to blur/block the preferredretinal location of the amblyopic second eye. In such a way, the visualsystem of the subject is encouraged to use the anatomical fovea of theamblyopic eye.

Exemplary embodiments of the teachings herein suitable for treatingamblyopia (using an optical device 10 with a single active opticalelement 24 as depicted in FIGS. 1A-1C) is depicted with reference toFIGS. 6A and 6B, a view of optical device 10 from the back toward theproximal side. In FIG. 6A the gaze direction of eye 22 a is straightahead. In FIG. 6B the gaze direction of eye 22 a is to the left.

The subject to be treated has amblyopia where the left eye, (first eye22 a) is the dominant non-amblyopic eye and the right eye (second eye 22b) is the amblyopic eye.

Before first eye 22 a is a (first) lens 12 with a (first) active opticalelement 24. In some embodiments, (first) lens 12 is a plano lens whichprimary purpose is to physically support (first) active optical element24 in place before first eye 22 a. In alternate embodiments, (first)lens 12 is a refracting lens configured as known in the art ofophthalmology, to at least partially correct the vision of first eye 22a, preferably, to optimally correct the vision of first eye 22 a.

When optical device 10 is operated, the controller (not depicted) uses(first) active optical element 24 with reference to an eye tracker 26 totrack the gaze direction of first eye 22 a to create an image mask 54.Mask 54 comprises a first zone 54 a and a second zone 54 b. Lightreflected from an object that passes through first zone 54 a to reachthe central portion of the visual field of first eye 22 a while lightreflected from an object that passes through second zone 54 b reachesportions of the retina of first eye 22 a that do not correspond to thecentral portion of the visual field.

In embodiments where the changeable optical property of the pixels of(first) active optical element 24 is light transmission, the pixels offirst zone 54 a are all set for a light transmission lower than thelight transmission of the pixels of second zone 54 b. The pixels offirst zone 54 a are set to a light transmission that is sufficiently lowto degrade the vision of the central portion of the visual field offirst eye 22 a to the extent that amblyopic second eye 22 b is used. Thepixels of second zone 54 b are typically, but not necessarily set forthe higher light transmission, even maximal light transmissiontherethrough. In such embodiments, mask 54 degrades the central portionof the visual field of non-amblyopic first eye 22 a to effectively haveinferior vision compare to that of amblyopic second eye 22 b so thatamblyopic second eye 22 b is used, while the non-central portion of thevisual field of non-amblyopic first eye 22 a is not substantiallydegraded, allowing image fusion.

In embodiments where the optical property with a changeable value is aproperty of the pixels that provides controllable optical power foractive optical element 24, the pixels of first zone 54 a are all set forblurring (defocusing) of light onto the central portion of the visualfield compared to the focusing of the pixels of second zone 54 b ontothe non-central portion of the visual field. Preferably, the pixels offirst zone 54 a are set to a degree of blurring that is sufficiently lowto degrade the vision of the central portion of the visual field offirst eye 22 a to the extent that amblyopic second eye 22 b is used. Thepixels of second zone 54 b are typically, but not necessarily set forfocusing light onto the non-central portion of the visual field so thatimages in the non-central vision of first eye 22 a are focused andsharp. In such embodiments, mask 54 causes the central portion of thevisual field of non-amblyopic first eye 22 a to effectively haveinferior vision to that of second eye 22 b so that amblyopic second eye22 b is used, while the non-central portion of the visual field ofnon-amblyopic first eye 22 a is substantially unchanged or evenimproved, allowing image fusion. Alternatively or additionally, in someembodiments, the pixels of second zone 54 b are set to compensate foraberrations in (first) lens 12. Alternatively or additionally, in someembodiments the pixels of second zone 54 b are set to be neutral,neither focusing nor de-focusing light.

In embodiments where the pixels of (first) active optical element 24have both changeable properties, any suitable combination of the aboveis used to achieve the desired goal: mask 54 degrading the centralportion of the visual field of non-amblyopic first eye 22 a toeffectively have inferior vision to that of second eye 22 b so thatamblyopic second eye 22 b is used, while the non-central portion of thevisual field of non-amblyopic first eye 22 a is substantially unchangedor improved, allowing image fusion.

With regards to amblyopic second eye 22 b, when optical device 10depicted in FIGS. 6A and 6B is a monocular optical device, in someembodiments, component 34 before second eye 22 b is absent. Inalternative such embodiments, component 34 is a transparent plano lens,primarily present to protect second eye 22 b and to provide a moreaesthetic appearance to increase subject compliance.

With regards to amblyopic second eye 22 b, when optical device 10depicted in FIGS. 6A and 6B is a binocular optical device, second lens38 is a transparent refracting lens, configured as known in the art ofophthalmology for correcting vision defects of second eye 22 b,preferably optimal correction as known in the art of ophthalmology.

In some embodiments, a binocular optical device such as optical device44 depicted in FIGS. 4A-4C comprising a second active optical element 50associated with second lens 38 is configured for treating amblyopia. Insuch embodiments, degrading the visual field of the amblyopic eye is asdescribed above with reference to FIGS. 6A and 6B. In some suchembodiments, second lens 38 is a plano lens which primary purpose is tophysically support second active optical element 50 in place beforeamblyopic second eye 22 b. In some embodiments, second lens 38 is arefracting lens, configured as known in the art of ophthalmology forcorrecting vision defects of amblyopic second eye 22 b, preferablyoptimal correction. For example, in cases where amblyopic second eye 22b suffers from anisometropia, correction by second lens 38 and/or secondactive optical element 50 (if configured that the optical property witha changeable value is a property of the pixels that providescontrollable optical power).

Macular Vision Damage

AMD (age-related macular degeneration) is a disease of the eyecharacterized by progressive loss of central vision due to degenerationof the macula. Often, a subject suffering from AMD develops apseudofovea. Specifically, the brain selects one or morestill-functioning portions of the retina and uses these portions forvision instead of the damaged portions of the retina. Due to theinherent lower density of light-sensing cells in the non-foveal portionsof the retina, such pseudofovea do not restore vision but do allow aperson to function.

For assisting and training of a subject with macular vision damageaccording to the teachings herein, an optical device is provided. Thecontroller of the provided optical device is configured so as to createan image mask that stimulates a selected retinal area outside the foveaforcing the use of a selected pseudofovea by one eye (the first eye) orboth eyes (the first eye and the second eye). For brevity and clarity,the below description will relate to assisting and training of a singleeye using an optical device having a lens and an active optical element.It is understood that in embodiments having an optical device with afirst lens and a first active optical element for a first eye, and asecond lens and a second active optical element for a second eye, thebelow description relates to the first lens and first active opticalelement for the first eye and, in embodiments where both eyes aretreated also relates to the second lens and second active opticalelement for the second eye.

According to the teachings herein, an optical device is configured andused to assisting and training a first eye of a subject suffering frommacular vision damage. Such configuration and use are effective fordeveloping a pseudofovea, improving the vision of the first eye.Specifically, an optical device is provided with a lens and an activeoptical element so that at least part of the visual field of the firsteye is covered by both the lens and the active optical element.

In some embodiments, the lens is a plano lens. Alternatively, inpreferred embodiments, the lens is a refracting lens configured tocorrect the vision of the first eye in the usual way as is known to aperson skilled in ophthalmology, preferably optimal such correction.

The active optical element and controller are together configured tocreate an image mask that allows only a narrow visual field for apseudofovea of the first eye.

For configuration of the optical device, a health-care professional suchas an ophthalmologist identifies a pseudofovea or a portion of theretina that is chosen as a candidate to be a pseudofovea.

In embodiments where the optical property with a changeable value is aproperty of the pixels that provides controllable optical power for theactive optical element, the data and parameters are set so that lightreflected from an object to be viewed by the pseudofovea is focused,preferably as focused as possible, so that an image of the object formedon the pseudofovea is focused and is therefore more visible.Additionally, in some such embodiments, light reflected from an objectto be viewed by portions of the visual field of the eye other than thepseudofovea are defocused and therefore degraded.

In embodiments where the active optical element includes pixels with achangeable value for light transmission, the data and parameters are setso that light reflected from an object to be viewed by the pseudofoveapasses through pixels that are all set for a light transmission higher(preferably maximal light transmission) than the light transmission ofthe pixels that correspond to portions of the visual field of the eyeother than the pseudofovea. As a result, the portions of the image ofthe object formed on the pseudofovea is easily visible and sharpcompared to the portions of the image of the object formed on the restof the retina, so that the brain of the subject preferably uses theparafovea. In some such embodiments, light reflected from an object tobe viewed by portions other than the pseudofovea passes through pixelsthat are set to transmit very little or even no light.

In such a way, the active optical element is used to create an imagemask that, when activated, leads to the eye having virtual tunnelvision, the tunnel being actively centered on the pseudofovea withreference to the eye tracker.

Thus, in some embodiments configured for assisting and training ofmacular vision damage, the image mask divides the active optical elementinto at least two different zones:

-   -   a first zone of the active optical element corresponding to a        non-foveal portion of the visual field of the eye defining a        pseudofovea; and    -   a second zone of the active optical element corresponding to        portions of the retina surrounding the pseudofovea,

-   so that all parts of the active optical element corresponding to the    pseudofoveal first zone are less opaque (e.g., have greater light    transmission and/or are more focused) than all parts of the active    optical element corresponding to the non-pseudofoveal second zone.

In some embodiments, the first pseudofoveal zone of the active opticalelement are such that the pseudofovea has angular dimensions of morethan about 1° and less than about 8°.

An exemplary embodiment of the teachings herein suitable for treatingmacular degeneration using a device 10 with a single active opticalelement 24 as depicted in FIGS. 1A-1C is depicted with reference toFIGS. 6A and 6B. In FIG. 6A, the gaze direction of eyes 22 a and 22 b isstraight ahead. In FIG. 6B, the gaze direction of eyes 22 a and 22 b isto the left. For clarity and brevity, in the following descriptioncomponent 12 will be referred to as lens 12, but it is understood thatthis refers also to first lens 12. Similarly, component 24 will bereferred to as active optical element 24, but it is understood that thisrefers also to first active optical element 24.

The subject to be assisted and trained has macular degeneration where ahealth-care professional decided to stimulate development of apseudofovea in left eye, first eye 22 a.

Before first eye 22 a is a lens 12 with an active optical element 24. Insome embodiments, lens 12 is a plano lens which primary purpose is tophysically support active optical element 24 in place before first eye22 a. In preferred embodiments, lens 12 is a refracting lens configuredas known in the art of ophthalmology, to at least partially correct thevision of first eye 22 a, preferably to the maximum extent possible.

When optical device 10 is operated, the controller (not depicted) usesactive optical element 24 with reference to an eye tracker 26 to trackthe gaze direction of first eye 22 a to create a mask 54. Mask 54comprises a first zone 54 a and a second zone 54 b. Light reflected froman object that passes through first zone 54 a to reach the pseudofoveaof first eye 22 a while light reflected from an object that passesthrough second zone 54 b reaches portions of the retina of first eye 22a other than the pseudofovea.

In embodiments where the changeable optical property of the pixels ofactive optical element 24 is light transmission, the pixels of firstzone 54 a are all set for a light transmission that is higher than thelight transmission of the pixels of second zone 54 b. Preferably, thepixels of first zone 54 a are set for the highest possible lighttransmission while pixels of second zone 54 b are set for the lowestpossible light transmission. In such embodiments, mask 54 causes firsteye 22 a to effectively have tunnel vision where the only portion of theretina that is stimulated is the pseudofovea while the vision of therest of the retina is degraded.

In embodiments where the changeable optical property of the pixels ofactive optical element 24 is a property of the pixels that providescontrollable optical power for the active optical element, the pixels offirst zone 54 a are all set for greater focusing of light onto thepseudofovea compared to the focusing of the pixels of second zone 54 b.In some embodiments, the pixels of first zone 54 a are set for optimalfocusing of reflected light onto the pseudofovea of first eye 22 a.Alternatively or additionally, in some embodiments, the pixels of firstzone 54 a are set to compensate for aberrations in (first) lens 12.Alternatively or additionally, in some embodiments the pixels of secondzone 54 b are set to be neutral, neither focusing nor de-focusing light.In some embodiments, the pixels of second zone 54 b are set to defocuslight onto portions of the retina of first eye 22 a that do notcorrespond to the pseudofovea, thereby degrading the vision of thenon-pseudofovea portions of the retina.

In embodiments where the pixels of active optical element 24 have bothchangeable properties, any suitable combination of the above is used. Inpreferred embodiments, the light transmission of pixels of second zone54 b are set for minimal light transmission, the light transmission ofpixels of first zone 54 a are set for maximal light transmission, andthe pixels of first zone 54 a are set for optimal focusing of reflectedlight onto the pseudofovea of first eye 22 a and for correction ofaberrations in first lens 12.

The above description related to use of an optical device 10 fordeveloping a pseudofovea of first eye 22 a. In some embodiments,component 38 before second eye 22 b is absent or plano lens.Alternatively, in some embodiments, component 38 before second eye 22 bis a refracting lens for correcting vision defects of second eye 22 b asknown in the art of ophthalmology. Alternatively, an optical devicehaving a second active optical element before the second eye, such asdevice 48 depicted in FIGS. 4A-4C is used for concurrently developing apseudofovea of second eye 22 b. In such embodiments, the configurationand use of such a second active optical element and associated secondlens is as described above for first active optical element 24 and firstlens 12

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which the invention pertains. In case of conflict, thespecification, including definitions, takes precedence.

As used herein, the terms “comprising”, “including”, “having” andgrammatical variants thereof are to be taken as specifying the statedfeatures, integers, steps or components but do not preclude the additionof one or more additional features, integers, steps, components orgroups thereof.

As used herein, the indefinite articles “a” and “an” mean “at least one”or “one or more” unless the context clearly dictates otherwise.

As used herein, when a numerical value is preceded by the term “about”,the term “about” is intended to indicate +/−10%.

As used herein, a phrase in the form “A and/or B” means a selection fromthe group consisting of (A), (B) or (A and B). As used herein, a phrasein the form “at least one of A, B and C” means a selection from thegroup consisting of (A), (B), (C), (A and B), (A and C), (B and C) or (Aand B and C).

Embodiments of methods and/or devices described herein may involveperforming or completing selected tasks manually, automatically, or acombination thereof. Some methods and/or devices described herein areimplemented with the use of components that comprise hardware, software,firmware or combinations thereof. In some embodiments, some componentsare general-purpose components such as general purpose computers ordigital processors. In some embodiments, some components are dedicatedor custom components such as circuits, integrated circuits or software.

For example, in some embodiments, some of an embodiment is implementedas a plurality of software instructions executed by a data processor,for example which is part of a general-purpose or custom computer. Insome embodiments, the data processor or computer comprises volatilememory for storing instructions and/or data and/or a non-volatilestorage, for example, a magnetic hard-disk and/or removable media, forstoring instructions and/or data. In some embodiments, implementationincludes a network connection. In some embodiments, implementationincludes a user interface, generally comprising one or more of inputdevices (e.g., allowing input of commands and/or parameters) and outputdevices (e.g., allowing reporting parameters of operation and results.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the scope of the appendedclaims.

Citation or identification of any reference in this application shallnot be construed as an admission that such reference is available asprior art to the invention.

Section headings are used herein to ease understanding of thespecification and should not be construed as necessarily limiting.

1. A wearable optical device for a human subject, comprising: a. atransparent lens having a distal surface and a proximal surface; b. awearable frame configured, when worn by a human subject, to maintainsaid proximal surface of said lens in front of a first eye of thesubject at a distance of not less than 5 mm and not more than 50 mm fromthe surface of the cornea of the first eye so that at least part of thevisual field of the first eye is covered by said lens when the gazedirection of the first eye is straight ahead; c. a transparent pixelatedactive optical element comprising at least 100 independently-addressablepixels, each one of said pixels having an optical property with achangeable value, the active optical element physically associated withsaid frame and/or said lens so that at least part of the visual field ofthe first eye is covered by both said lens and said active opticalelement; d. an eye tracker configured to determine and report the gazedirection of the first eye; and e. a controller having a digital memoryconfigured to: i. receive from said eye-tracker a determined gazedirection of the first eye; and ii. at a repetition rate, set a valuefor a said optical property of said at least 100 pixels of said activeoptical element so as to create an image mask through which at leastsome of the light reaching the first eye passes through, therebymodifying the image formed on the retina of the first eye, wherein saidvalue for a said optical property is based on a received gaze directionand the optical power of said lens, and the device further comprising: apupil size determiner configured to determine and report the size of thepupil of the first eye, and said controller is configured to receivefrom said pupil size determiner a determined pupil size of the firsteye, and said value for a said optical property is also based on areceived pupil size.
 2. The optical device of claim 1, wherein saidpupil size determiner and said eye tracker are the same component. 3.The optical device of claim 1, wherein said pupil size determiner is acomponent different from said eye tracker.
 4. The optical device ofclaim 1, wherein said frame and said lens are together configured tothat at least 30% of the visual field of the first eye is covered bysaid lens when the gaze direction of the first eye is straight ahead. 5.The optical device of claim 1, wherein said part of the visual field ofthe first eye that is covered by both said lens and said active opticalelement is at least 20% of the visual field of the first eye when thegaze direction of the first eye is straight ahead
 6. The optical deviceof claim 1, wherein said active optical element comprises at least 400said independently addressable pixels.
 7. The optical device of claim 1,wherein said optical property with a changeable value is a property ofthe pixels that provides controllable optical power for the activeoptical element.
 8. The optical device of claim 1, wherein said opticalproperty with a changeable value is light transmission of the pixels. 9.The optical device of claim 8, wherein said controller is configured tochange the light transmission through said active optical element tobalance the intensity of light reaching the two eyes of the subjectbased on a determined pupil size.
 10. The optical device of claim 1,wherein said optical property is both a property of the pixels thatprovides controllable optical power for the active optical element andlight transmission of the pixels.
 11. The optical device of claim 10,wherein said controller is configured to change the light transmissionthrough said active optical element to balance the intensity of lightreaching the two eyes of the subject based on a determined pupil size.12. The optical device of claim 1, wherein said lens is a plano lens.13. The optical device of claim 1, wherein said lens is a refractinglens having a non-zero optical power.
 14. The optical device of claim13, wherein said lens is a simple refracting lens having a singleconstant optical power over the entire said lens.
 15. The optical deviceof claim 13, wherein said lens is a complex refracting lens having atleast two portions, each said portion having a different optical power.16. The optical device of claim 13, wherein said lens is configured todegrade at least a portion of the visual field of the first eye of thesubject.
 17. The optical device of claim 13, wherein said controller isconfigured to create a said image mask having a portion that decreasesan image modification done by said lens.
 18. The optical device of claim13, wherein said controller is configured to create a said image maskhaving a portion that amplifies an image modification done by said lens.19. The optical device of claim 1, wherein said image mask is created insuch a way so that the image formed on the retina of the first eye is atherapeutic image.
 20. The optical device of claim 1, wherein twosucceeding image masks created based on two respective received gazedirections are created so that the modifying of an image formed on theretina of the first eye by said two succeeding images is substantiallythe same.